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| United States Patent |
6,072,712
|
|
Russell
|
June 6, 2000
|
Compact optical random access memory having a refractive-reflector lens
Abstract
A compact optical memory is disclosed in which data are stored in an
optical data layer capable of selectively altering light such as by
changeable transmissivity, reflectivity, polarization, and/or phase. The
data are illuminated by controllable light sources and an array of
multi-surface diffractive imaging lenslets which cause a data image to be
projected onto an array of light sensors by reflecting, hence folding the
image rays, by means of a Mangin mirror that both reflects and optically
modifies the light rays to redirect them onto the sensor array located
substantially coplanar with the data layer. Data are organized into an
annular array of patches (called pages). By selective illumination of each
data page, one of the lenslets images the selected data page onto a
central image plane where the sensor array is located. Light in the data
image pattern strikes different ones of the arrayed light sensors, thereby
outputting a pattern of binary bits in the form of electrical data
signals. By selectively and sequentially illuminating different ones of
the data regions (pages) on the data layer, correspondingly different data
patterns are imaged by the corresponding lenslets onto the common sensor
array, thereby enabling many stored data images to be retrieved by
multiplexing at electro-optical speed.
| Inventors:
|
Russell; James T. (Bellevue, WA)
|
| Assignee:
|
Ioptics, Inc. (Issaquah, WA)
|
| Appl. No.:
|
311974 |
| Filed:
|
May 14, 1999 |
| Current U.S. Class: |
365/120; 365/127 |
| Intern'l Class: |
G11C 013/04; G11C 011/42 |
| Field of Search: |
365/106,114,120-124,127
|
References Cited
U.S. Patent Documents
| 5559732 | Sep., 1996 | Birge | 365/120.
|
Primary Examiner: Fears; Terrell W.
Attorney, Agent or Firm: Rupnick; Charles J.
Parent Case Text
CROSS REFERENCE TO RELATED PATENTS AND APPLICATIONS
This is a continuation-in-part of U.S. application Ser. No. 08/920,847
filed Aug. 29, 1997, now U.S. Pat. No. 5,926,411, which is a division of
U.S. application Ser. No. 08/256,202 filed Jun. 28, 1994, now U.S. Pat.
No. 5,696,714 which in turn is a continuation-in-part of U.S. application
Ser. No. 07/815,924 filed Dec. 30, 1991, now U.S. Pat. No. 5,379,266 all
by James T. Russell; a continuation-in-part of U.S. application Ser. No.
09/180,393 filed on Nov. 5, 1998, as a national entry of of international
application PCT/US97/07967 filed May 8, 1997 which is a Provisional of
U.S. application Ser. No. 60/017,502 filed May 10, 1996 by Loren Laybourn,
Richard E. Blahut and James T. Russell; and a Provisional of 60/085,715
filed May 15, 1998.
Claims
I claim:
1. An optical data system comprising:
a substantially planar optical data means for storing data as light
altering characteristics and being organized into a plurality (P) of
juxtaposed data regions each having capacity to store (B) bits of data and
arrayed in a planar annular pattern having a light transmissive window
substantially centered with respect to said annular pattern;
controllable light source means disposed proximate a first side of said
planar optical data means for selectively illuminating at least one of
said separate data regions of said optical data means;
data imaging lens optics arranged in such proximity to and in optical
registration with said juxtaposed data regions so that the image resolving
power thereof is substantially uniform over the field of view of that data
region to form an image thereof on a common image surface;
a composite refractive and reflective optical device surface spaced from
and generally parallel to and in optical alignment with a second side of
said planar optical data means for refracting and reflecting a data image
of each of said data regions back and inwardly toward said center of said
annular pattern;
sensor means having a plurality (S) of juxtaposed light sensors arranged
proximate said planar optical data means in registration with said
transmissive window to provide said common image surface for sensing data
as a light image corresponding to an illuminated data region; and
data signal output means coupled to said sensor means for outputting data
signals representing said data of an illuminated and imaged data region.
2. The optical data system of claim 1, wherein said composite refractive
and reflective device is a Mangin mirror.
3. The optical data system of claim 1, further comprising a diffractive
window element disposed between the second surface of said data means and
said composite refractive and reflective device for correcting imaging of
data ray bundles prior to striking said sensor means.
4. The optical data system of claim 1, wherein said sensor means is
generally coplanar with said data record means.
Description
BACKGROUND OF THE INVENTION
The invention concerns method and apparatus of optically storing and
retrieving mass digital data stored as light altering characteristics on
an optical material and providing fast random access retrieval.
Optical memories of the type having large amounts of digital data stored by
light modifying characteristics of a film or thin layer of material and
accessed by optical addressing without mechanical movement have been
proposed but have not resulted in wide spread commercial application. The
interest in such optical recording and retrieval technology is due to its
projected capability of faster retrieval of large amounts of data compared
to that of existing electro-optical mechanisms such as optical discs, and
magnetic storage such as tape and magnetic disc, all of which require
relative motion of the storage medium.
For example, in the case of optical disc memories, it is necessary to spin
the record and move a read head radially to retrieve the data, which is
output in serial fashion. The serial accessing of data generally requires
transfer to a buffer or solid state random access memory of a data
processor in order to accommodate high speed data addressing and other
data operations of modern computers. Solid state ROM and RAM can provide
the relatively high access speeds that are sought, but the cost, size, and
heat dissipation of such devices when expanded to relatively large data
capacities limit their applications.
Examples of efforts to provide the relatively large capacity storage and
fast access of an optical memory of the type that is the subject of this
invention are disclosed in the patent literature such as U.S. Pat. No.
3,806,643 for PHOTOGRAPHIC RECORDS OF DIGITAL INFORMATION AND PLAYBACK
SYSTEMS INCLUDING OPTICAL SCANNERS and U.S. Pat. No. 3,885,094 for OPTICAL
SCANNER, both by James T. Russell; U.S. Pat. No. 3,898,005 for a HIGH
DENSITY OPTICAL MEMORY MEANS EMPLOYING A MULTIPLE LENS ARRAY; U.S. Pat.
No. 3,996,570 for OPTICAL MASS MEMORY; U.S. Pat. No. 3,656,120 for
READ-ONLY MEMORY; U. S. Pat. No. 3,676,864 for OPTICAL MEMORY APPARATUS;
U.S. Pat. No. 3,899,778 for MEANS EMPLOYING A MULTIPLE LENS ARRAY FOR
READING FROM A HIGH DENSITY OPTICAL STORAGE; U.S. Pat. No. 3,765,749 for
OPTICAL MEMORY STORAGE AND RETRIEVAL SYSTEM; and U.S. Pat. No. 4,663,738
for HIGH DENSITY BLOCK ORIENTED SOLID STATE OPTICAL MEMORIES. While some
of these systems attempt to meet the above mentioned objectives of the
present invention, they fall short in one or more respects.
For example, some of the systems proposed above have lens or other optical
structure not capable of providing the requisite resolution to retrieve
useful data density. The optical resolution of the data image by these
prior lens systems does not result in sufficient data density and data
rate to compete with other forms of memory. Although certain lens systems
used in other fields such as microscope objectives are theoretically
capable of the needed resolutions, such lens combinations are totally
unsuited for reading data stored in closely spaced data fields. Another
difficulty encountered with existing designs is the practical effect of
temperature and other physical disturbances of the mechanical relationship
between the data film or layer, the lens assemblies and the optical
sensors that convert the optical data to electrical signals. For example,
the thermal expansion effects of even moderate density optical memories of
this type can cause severe misregistration between the optical data image
and the read out sensors. Similar difficulties are encountered in the
required registration between the recording process and the subsequent
reading operations. Intervening misregistration of the high density
optical components can cause significant data errors if not total loss of
data.
A single reflection folded path optical memory device, such as disclosed in
my U.S. Pat. No. 5,436,871 reduces somewhat the system dimension along the
optical axis; the direction that has been referred to as thickness or
height. But it is desirable to further reduce the thickness without
sacrificing performance.
The essential function of the mirror in the folded image memory is the same
as a "field" lens in the above mentioned patents and applications. The
mirror accepts an array of collimated beams, one from each bit, spot or
mark, and directs each beam to, and focuses each beam on, the focal plane,
i.e., the sensor array. It is similar to an astronomical telescope where
the parabolic mirror accepts parallel ray bundles from an array of stars,
and directs and focuses each star bundle on to the focal plane. If it is
desired to reduce the thickness, that is, the distance from the mirror
apex to the sensor plane, the focal length of the mirror must be reduced.
But if it is desired to retain the same chapter capacity, i.e., retain the
same size data record, several problems arise. First, the beams that are
furthest off-axis will become astigmatic. This is a fundamental failing of
a simple parabolic that is troublesome even in astronomical telescopes.
Wide field telescopes require additional corrector elements. Second, the
angle that the off-axis beams make with the sensor plane may become so
large that the image will be geometrically smeared, or may even approach
the sensor from the rear; obviously an ineffective configuration. The
solution for an astronomical instrument is to add an additional optical
element, for example, a corrector plate some distance in front of the
mirror. But in the folded ORAM system, there is limited room for
additional discrete elements, and the desired compression is much more
severe than usually contemplated for astronomical instruments. The
solution, in comparison to my original folded patent, is to make existing
optical elements do multiple functions.
Accordingly, it is an object of this invention to provide an optical mass
memory having random accessibility in a relatively compact size comparable
to or even smaller than tape and compact disc storage mechanisms and yet
still serving data processing equipment in the same manner that solid
state random access memories move data into and from the processor's data
bus.
SUMMARY OF THE INVENTION
In an optical data storage and retrieval system of the folded path type
disclosed herein, a composite reflective and refractive lens-mirror is
used to further reduce the thickness of the storage device while
maintaining needed effective length of the optical path. Data are stored
in an optical data layer capable of selectively altering light such as by
changeable transmissivity, reflectivity, polarization, and/or phase. In
the case of a transmissive data layer, data bits are stored as transparent
spots on a thin layer of material and are illuminated by controllable
light sources. An array of imaging lenslets project an optically enlarged
image of the illuminated data onto an array of light sensors. The layer of
data is organized into a plurality of regions or patches (called pages)
and by selective illumination of each data page one of the lenslets images
the data page onto the array of light sensors.
Transmitted page data, in this case light passed through the transparent
bit locations on the data layer, and the constituent rays are folded back
toward a centrally located sensor array of light detectors by the
composite reflective and refractive optics. In the preferred embodiment,
the composite optics is a Mangin-type lens. The thusly reflected and
refracted rays strike different ones of the arrayed light detectors,
outputting the stored and retrieved information in the form of electrical
data signals. By selectively and sequentially illuminating different ones
of the data regions (pages) on the data layer, correspondingly different
data patterns are imaged by the corresponding lenslets and the composite
reflective and refractive optics onto the common photosensor array,
thereby enabling many data pages to be multiplexed at electro-optical
speed to a data interface output associated with the photosensor array.
Embodiments of data storage and retrieval systems related to the present
invention are disclosed in the above-referenced related application Ser.
No. 07/815,924, now U.S. Pat. No. 5,379,266, as read-only devices,
write-only devices, and read/write devices. In accordance with the
preferred embodiment of the present invention, the pages or regions of
data are arrayed in a substantially annular, planar pattern on a data
layer that is in turn preferably bonded to an annular multi-surface lens
array, also of annular configuration. Individual, selected data regions or
pages are illuminated by a solid state emitter, such as an LED or laser
diode. The lenslets of the multi-surface lens system array collect light
from the data layer and direct it toward a substantially planar reflective
surface that is disposed substantially parallel to and spaced from the
annular data layer and annular lenslet array. The reflective surface both
reflects and optically alters the light rays that are to form the data
image. This reflection redirects and folds the image back toward the
center of the annular lenslet and data arrays where the data page image is
formed. To receive this reflected and hence folded image, a planar array
of solid state sensors are positioned at an image plane in registration
with a centered region of the data and lenslet arrays, preferably at a
plane that is on the opposite side of the data layer from the reflector.
The optical prescriptions of the lenslets and composite reflective and
refractive optics are designed for the folded optical path so that the
data images are convergent on an imaginary axis passing through the center
of the annular data and lenslet arrays. After reflection, the data image
from a selected data region or page location on the data array are drawn
back toward the center of the assembly to fall precisely on the detector
elements of the sensor array. This configuration, in which the data are
distributed in an annular array surrounding the centrally located sensor
array together with the optically modifying reflector, provides for a
compact optical memory assembly. A relatively large amount of data area or
surface area for data is available for being imaged, on a selective page
by page basis, onto the common centrally located sensor array, in a
compact, efficient geometry. The optical distance available for imaging
the data is essentially twice the height or thickness of the assembly,
i.e., the distance between the data layer plane and the reflector plane.
In the preferred embodiment, the annular data layer and annular lenslets
are affixed on a removable data/lenslet sandwich card that has an opening
or optically transparent window at the center of the arrays. The data/lens
card is removably inserted into a reader that houses the sources of light
(emitter), sensor array, reflector and interface electronics. Further
still, the preferred form of the lens surfaces of the data/lenslet
sandwich card are diffractive with a computed prescription that takes into
account the resolution requirements of the data as well as the location of
the data images relative to the center of the annular arrays. The
electronics that support the light emitters and sensors are preferably
mounted adjacent to or integrated with, as by large scale integration
(LSI), the emitters and/or sensors to provide further efficiencies and
compactness in the overall product.
As a further aspect of the preferred embodiment, a lens element is mounted
proximate to the exiting rays from the lenslet array to bend or tilt the
bundle of rays toward the optical axis of the structure so that the
composite reflective and refractive optics, such as preferably provided by
the Mangin-type lens-mirror, requires less severe alteration of the rays
to redirect them to the centrally located sensor array. This intervening
lens element is preferably a diffractive surface in a transparent window
between the lenslet-data card and the Mangin-type optical reflective lens
structure.
Still another aspect of this preferred form of the lenslet array is that
the first surface of each lenslet, i.e., adjacent the data layer, is
aspherically prescribed to enhance the optical resolution of the
exceedingly small and dense patch of data that is to be imaged. As
indicated above, this first surface and at least one second surface of the
lenslet array are preferably diffractive. The annular data layer and
annular lenslet array together with the transparent immersion/bonding
layer can be fabricated at a cost that allows the structure to be
fabricated and effectively used as a replaceable data card.
It is therefore seen that the present invention provides an enormous data
storage capability having random access speeds that approach, if not
exceed, the fastest solid state RAMs and ROMs. Moreover, the organization
of the data output capability of the present invention enables unusually
large data words to be accessed virtually at the same instant, such as at
a single clock time. Since the entire data page, when imaged on the
photosensor array, conditions the array to output all of the data from
that page at any given instance, the size of the output word is limited
only by the number of bits in the sensor array and the addressing
electronics cooperating with the sensor array. Since the array itself can
be interrogated along rows and columns of data, each of which may be on
the order of 1,000 bits per row or column, this allows the system of the
present invention to output a data word on the order of 1,000 bits, or
selected and variable portions thereof as needed. Such relatively large
output words provide important applications of the present invention to
such systems as computer graphics, "correlation engines" of computer based
industrial systems, and other computerized or digital based systems.
These and other features, objects, and advantages of the invention will
become apparent to those skilled in the art from the following detailed
description and appended drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a section view taken along a vertical cutting plane of an
embodiment of the optical memory having an image collector including a
folding reflector in the form of a Mangin-type mirror, arrays of emitters
and sensors, and a slot or spacing therebetween for receiving a data/lens
sandwich card or cartridge containing annular arrayed data and superposed
imaging lenslets.
FIG. 2 is an isometric view of the memory device of FIG. 1 in which various
components are cutaway in pie sections to reveal the interior
configuration and optical paths of the light image forming rays.
DETAILED DESCRIPTION
In FIGS. 1 and 2, the rays of the data image emanating from the data lens
card are folded by reflection and modified by refraction in a composite
optical structure having surfaces 6,7,8,9. In this preferred embodiment
the optical structure is made into a type of Mangin lens-mirror. The
surface 7 of the Mangin optics remote from the data-lenslet card is
reflective and contoured and the refractive lens body 8 and entry and exit
surfaces 6 and 9 respectively are shaped so as to draw the image rays back
toward the optical center of the data-lenslet card where the sensor array
of detectors 108 is located at optical surface 17. A classic Mangin mirror
is a combination of a spherical reflector, and a spherical refractive
lens. The combination can be made to function as a single parabolic
mirror. It was originally invented for use on searchlights, where it gave
the required parabolic function, the glass lens part protected the mirror
from the carbon arc, and is considerably easier to make in large sizes.
Because the field of data in the present case is relatively large, the
classic parabolic surfaces are modified in the preferred embodiment to be
aspheric. Making both surfaces 6 and 9 aspheric also requires corrections
incorporated to give a true image hence more reliable data retrieval.
Also it is desirable to make the optical system invariant to location of
the data page on the card holding the layer or film at surface 0 shown in
FIG. 1. That is, if the record is inadvertently displaced laterally, it is
advantageous if the image does not move. In optical memory design of this
type, the rays from each point on a page are collimated before entering
the optics that function as the "field" lens.
If conventional field lens optics were used, and if all page or patch
lenslets have about the same focal length, all of the data pages would
appear the same to the field lens subsystem, and all the constituent page
images would be always directed to, and focused on the sensor array. If a
page moves relative to the collection optics, the rays are still directed
to the same point on the sensor. But, in the embodiment described using
the Mangin-folded system, the ray bundles cannot be uniformly collimated
because the entrance angles must be modified across the chapter radius.
However, by placing a window having diffractive surface 4 in front of the
Mangin lens-mirror, the necessary angle and focal correction is provided
for the bundles or image rays as a function of device radius. The bundles
of rays are thereby collimated and parfocal as they exit the data-lens
sandwich card (hence before entering the diffractive surface 4 of the
window), and made invariant. By these techniques, the thickness of the
system can be significantly reduced as compared to previous designs.
With reference to FIGS. 1 and 2, a preferred form of the optical random
access memory 100 in accordance with the invention is shown with the
housing and light sources omitted for clarity and simplification. Memory
100 includes light sources (not shown), a data/lens card 104 with surfaces
0,2 respectively at the data layer and diffractive lenslets; sensor array
108 at a common effective surface 17, and interface electronics (not shown
here but fully disclosed in related U.S. application Ser. No. 07/815,924,
now U.S. Pat. No. 5,379,266, and international Application Ser. No.
PCT/US92/11356, the published specifications of which are incorporated
herein by reference). Data/lens card 104 with surfaces 0,2 is removable
and in use is inserted in a slot indicated by slot guides 139 in a housing
underlying a window having diffractive surface 4 and a transparent surface
11 so as to position an annular array of data regions or pages in
registration with a correspondingly shaped annular array of page selection
light sources (not shown). Sensor array 108 at surface 17 is fixed in the
housing coaxial with the Mangin lens-mirror at surfaces 6,7,8,9 for
receiving data page images sequentially selected and generated by
individual ones of light sources, and reflected (hence folded) by an
uppermost contoured concave reflective surface 7 of Mangin lens-mirror
6,7,8,9 overlying data/lens card 104 which is generally parallel with card
slot 139 and thus in position to collect image rays of an illuminated data
page or patch.
The annular configuration of the data/lens arrays on card 104 allows a
substantial increase in data storage over other proposed configurations,
and the reflective surface of Mangin lens-mirror 6,7,8,9 folds the data
image rays back toward the center of the data/lens annulus, where the
common sensor array 108 is positioned at surface 17, to yield a compact
optical memory reader.
Unitary data/lens card 104 with data and diffractive lens surfaces 0,2 is
fabricated as a bonded unit so that the array of lenslet systems at
surface 2 is fixed in spatial relation to the data layer 0. This structure
enhances the integrity of the optical registration between data and
imaging lenslets so that the card is installable and replaceable as a unit
while maintaining fixed spatial data-to-lens relationship.
To further enhance the readability by the sensor of the light image rays
emanating from data/lens card structure 104, and representing a selected,
illuminated data page, the image rays from each such page are passed
through a lenslet system having at least a first optical surface 2. This
optical lens surface is preferably diffractive. As described in related
U.S. and PCT applications, Ser. Nos. 07/815,924 (now U.S. Pat. No.
5,379,266) and PCT/US92/11356, the lens surface 2 is placed close to the
data layer 0 and is aspheric to collect a maximum amount of the data field
light in each page. A second diffractive surface may be used in some
applications to improve image quality.
Thus by disposing the sensor 108 beneath the data card at surface 17, the
improved imaging due to refraction by the card's transparent center is
accomplished together with the topology of a sensor 108 that is mounted on
the same or a coplanar integrated circuit substrate as that which supports
the light source array 106.
The data image projected onto sensor array 108 in this preferred embodiment
is generated from pages stored in a regular x-y grid pattern as shown in
FIG. 2. By illuminating selected regions or pages of the data layer, e.g.,
a single page, the image, as transformed by an associated lenslet system,
is enlarged, bent inwardly by diffractive surface 4 toward common
collector image surfaces 6,9 of the Mangin optics and shifted radially
inwardly, reflected, further modified by the optical prescription of the
Mangin lens-mirror 6,7,8,9 and then imaged on the sensor array 108 of
light sensing elements or detectors at surface 17.
The redirection of the image rays by the optical prescription of the
reflective surface 7 and refractive surfaces 6,9 of the Mangin optics
serves as a type of field lens, to collect and refocus the data page image
onto sensor at surface 17.
Thus, in operation, one of many pages of binary data is selected from
annular data layer 0 by energizing a chosen cell of annular arrayed light
sources indicated at 106. This causes data page light rays to emanate
toward and be reflected by Mangin optics 6,7,8,9 which distributes the
data bit rays that become the page image to strike the arrayed
photosensing detection elements of the sensor array. The data page image
has roughly the shape of a circle or many sided regular polygon and fills
the image plane on the upper surface 17 of the sensor array. The
individual data bits within a single data page are here arranged in
closely spaced rows and columns and at densities that use to advantage
high resolution optical films and other record media including but not
limited to photochemical films.
As described in related U.S. application Ser. No. 07/815,924, now U.S. Pat.
No. 5,379,266, and international Application Ser. No. PCT/US92/11356, the
data may be recorded onto surface 0 that is the data layer by
photochemical processes using a page composer and imaging optics to
successively expose each page or region on the data layer to a field of
data light bits, by direct photographic reproduction including contact
printing and/or molding or embossing from a master as in the case of
conventional compact disc records. The data bits are in a size range of
2.25 to 0.5 microns and a center-to-center spacing also in that range.
Each data page is formed by the amount of individual data bits that can be
collected and grouped into a cell and at the preferred density range of
2.times.10.sup.7 -4.times.10.sup.8 bits per cm.sup.2, it has been found
that about 150 thousand bits of data per page (or region) is an
advantageous quantity that results in the generation of a data image after
magnification that can be reliably sensed by photosensitive elements of
sensor array 108. In this case, the preferred embodiment provides an
optical image enlargement through the various lenslet systems and field
lens effect of surfaces 6,7,8,9 of approximately 20 to 30 times data
density on layer 0. Thus, assuming a mean magnification of 25.times., the
spacing of the projected image elements on the sensor array at surface 17
is on the order of 25 microns. A multi-sided or roughly circular cell for
sensing a page of data may thus contain one million data bit sensor
elements, assuming that a sampling ratio of 2.times.2 subarray of detector
pixels are used for each effective image bit, and that a suitable guard
band is provided at the sensor.
The particular structure and operation of the sensor array 108 and various
alternatives to the preferred embodiment are described in greater detail
in related U.S. application Ser. No. 07/815,924, now U.S. Pat. No.
5,379,266, and international Application Ser. No. PCT/US92/11356. Briefly,
each data bit which may be represented by a spot of light from the imaged
page, causes a photosensitive element of sensor array 108 to either
conduct or nonconduct depending on whether the data is a "1" or a "0" bit.
Although different forms of data layer may be employed, in the present
preferred embodiment data layer at surface 0 is a light transmissive mask
or film in which binary "1" bits are transmissive while binary "0" bits
are opaque or light blocking.
In the particular embodiments of FIGS. 1-2, the major radius of the
assembled collection of data pages in layer 0 is about 25 mm, and the
minor radius of the annulus about 8.5 mm. The sensor is about 10 mm
diameter. This provides about five times as many pages as would have been
the case without an imaging folding mirror, but with the same height.
Alternatively, the height is about half what it would have been for the
same data chapter size, collectively all pages.
TABLE
__________________________________________________________________________
EXAMPLES OF LENS AND REFLECTOR PRESCRIPTIONS FOR ORAM 100
__________________________________________________________________________
LENS DATA for FIG. 1
One Reflection System with Mangin type Mirror
SURFACE
RADIUS THICKNESS
APERTURE RADIUS
GLASS
NOTE
__________________________________________________________________________
0 -- 0.100000
0.200000 ULTEM
Data Surface
1 -- 1.766391
0.260000 ULTEM
2 -- 0.500000
0.260000 AK
ACRYLIC
Diff. Lens
3 -- 0.250000
0.260000 AIR
4 -- 1.000000
21.000000 ACRYLIC
Diff. Window
5 -- 8.383629
21.000000 P
AIR
6 -21.714598
4.000000
21.000000 P
BK7
7 -79.222200
-- 21.000000 P
REFLECT
Mirror
8 -- -4.000000 P
21.000000 P
BK7
9 -21.714598 P
-8.383629 P
21.000000 P
AIR
10 -- -1.000000
7.500000 ACRYLIC
Clear Window
11 -- -0.250000
7.500000 P
AIR
12 -- -0.500000
7.500000 P
ACRYLIC
13 -- -1.866391 P
7.500000 P
ULTEM
14 -- -0.100000
7.500000 P
AIR
15 -- -0.100000
4.000000 BK7
16 -- -- 4.000000 AIR
17 -- -- 4.000000 Sensor
__________________________________________________________________________
CONIC AND POLYNOMIAL ASPHERIC DATA
SURFACE
Conic Const.
__________________________________________________________________________
6 -25.754811
7 6.468963
9 -25.754811
__________________________________________________________________________
DIFFRACTIVE SURFACE DATA
2 DOE DFX
8 - ASYMMETRIC DIFFRACTIVE SRF
DOR 1 DWV
0.645000
KCO 1 KDP
--
DF0 -- DF1
-- DF2 -3.2093e-05
DF3
-0.442292
DF4 -- DF5
-0.438101
DF6 -- DF7
0.000861
DF8 -- DF9
0.000560
DF10 0.045746
DF11
--
DF12 0.039952
DF13
-- DF14 0.009346
DF15
--
DF16 -- DF17
-- DF18 -- DF19
--
DF20 -0.005878
DF21
-- DF22 -- DF23
-0.206938
DF24 -- DF25
-0.082237
DF26 -- DF27
-0.008902
2 DOE DFX
8 - ASYMMETRIC DIFFRACTIVE SRF
DOR 1 DWV
0.645000
KCO 1 KDP
--
DF0 -- DF1
-0.026974
DF2 1.9399e-05
__________________________________________________________________________
REFRACTIVE INDICES
SRF GLASS
RN1 RN2 RN3 VNBR TCE
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0 ULTEM
1.650783
1.652245
1.649365
225.975134
--
2 ACRYLIC
1.488490
1.488924
1.488069
571.701364
--
6 BK7 1.514682
1.515014
1.514362
789.290885
71.000000
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WAVELENGTHS
CURRENT WV1/WW1 WV2/WW2
WV3/WW3
__________________________________________________________________________
1 0.645000 0.635000
0.655000
1.000000 0.500000
0.500000
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Data in these tables describe a lens set prescription and Mangin
reflector-lens that would be effective for a page at the outer edge of the
record element. This is the optically most difficult location. Preferably,
data pages that are closer to the center have revised prescriptions for
the lenses, computed using a conventional lens design program such as the
one mentioned below, and inputting the radial offsets for the interior
lenslets. The spacings and the reflector remain the same.
A commercial lens design program called OSLO6 was used to do the design
shown in the table. The program is a product of Sinclair Optics, Inc.,
Fairport, N.Y.
While only particular embodiments have been disclosed herein, it will be
readily apparent to persons skilled in the art that numerous changes and
modifications can be made thereto, including the use of equivalent means,
devices, and method steps without departing from the spirit of the
invention.
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